Child maltreatment has well-established, wide-ranging, and long-term negative effects on children. Most children who have experienced maltreatment and are receiving services through the Child Welfare System (CWS) remain in their homes with their caregivers. While the need for parenting services is extensive, few intervention programs have proven to be efficacious in reducing child abuse and neglect within the CWS population, especially for infants and toddlers. It is essential that social service practitioners within the CWS delivery system are equipped to provide brief interventions to maltreating parents. This R01 proposal, Training Social Work Providers: Intervention for Maltreating Families of Infants and Toddlers, is an evaluation of a training program for social welfare providers to implement a brief attachment theory-based intervention to families who have been investigated for child abuse and neglect by Child Protective Services. The program (Promoting First Relationships [PFR]; Kelly, Buehlman, & Caldwell, 2000) will be tested at two levels: through social welfare practice and at the level of outcomes for children and families. Social service providers will be trained to deliver PFR to families under investigation for maltreatment by the Department of Social and Health Services, Snohomish County, Washington State. Subsequently, families under investigation by CPS will be recruited into the study and randomly assigned to the experimental group (receiving the PFR intervention) or to the comparison group (receiving the resource and referral). The specific aims of this study are to (1) Test the effectiveness of training community social welfare service providers in the use of attachment-based interventions by measuring their pre-training and post-training service provision strategies and interactions with maltreating families; (2) To test the effects of a relationship and attachment-based intervention with infants/toddlers of parents identified as maltreating by comparing them to a control group on rates of re-referral to CPS, severity of referral, and foster care placement; and (3) To conduct a test of the effectiveness of an attachment-based intervention on child well-being by comparing experimental and comparison groups on important outcomes (attachment security, emotional regulation, behavior, and developmental functioning). RELEVANCE Child maltreatment is a serious public health issue, affecting close to a million children nationally every year. The establishment of effective evidence-based interventions for high-risk families is essential to curtail the devastating long-term effects of maltreatment. The proposed study tests the feasibility and effectiveness of a well-documented relationship-based intervention (Promoting First Relationships) in improving outcomes for families referred to CPS for maltreatment.